using System;
using System.Collections.Generic;
using System.Text;
using NHibernate.Connection;
using System.Data.OracleClient;
using System.Configuration;
using System.Web.Configuration;
using System.Data;
using NHibernate.Util;
using NHibernate;

namespace Stanford.Slac.NHibernateUtil.Connection
{
   /// <summary>
   /// Provides connections to NHibernate from connection strings stored
   /// in the standard ASP.NET 2.0 web.config "connectionStrings" section.
   /// </summary>
   public class ConnectionStringsSectionConnectionProvider : ConnectionProvider
   {
      /// <summary>
      /// Gets an IDbConnection based on the connection name set in
      /// the hibernate.connection.connection_string setting of your nHibernate config.
      /// </summary>
      /// <returns>An IDbConnection of the type defined by the NHibernate dialect.</returns>
      /// <remarks>
      /// NOTE: The type of the IDbConnection is determined by the NHibernate
      /// hibernate.dialect setting, *not* the "providerName" attribute on the "add" element
      /// in the "connectionStrings" section of the config.
      /// </remarks>
      /// <seealso cref="System.Configuration.ConnectionStringSettings">System.Configuration.ConnectionStringSettings</seealso>
      public override System.Data.IDbConnection GetConnection()
      {
         ConnectionStringSettings settings = null;
         if (null != System.Web.HttpContext.Current)
         {   
            settings = WebConfigurationManager.ConnectionStrings[this.ConnectionString];
         }
         if (null == settings)
         {
            settings = ConfigurationManager.ConnectionStrings[this.ConnectionString];
         }
         if (null == settings || String.IsNullOrEmpty(settings.ConnectionString))
         {
            throw new HibernateException("Could not configure NHibernate.",
               new ArgumentException("hibernate.connection.connection_string",
                  "'" + this.ConnectionString + "' did not correspond to any defined connections in " +
                  "the connectionStrings section of the config file."));
         }

         IDbConnection conn = this.Driver.CreateConnection();
         conn.ConnectionString = settings.ConnectionString;
         conn.Open();
         return conn;
      }
   }
}